BIOLOGY OF CLOSTRIDIUM WELCHII 



417 



The guinea-pig is peculiarly susceptible to infection while 

 the rabbit is much more resistant. The rabbit succumbs, how- 

 ever, to the inoculation of a more virulent strain or a larger dose. 



The duration of the disease in these animals varies from a few 

 hours to several days, complete recovery from a local infection 

 taking one to three weeks. All degrees are observed from a very 

 mild local infection to a severe necrosis, resulting in the lique- 

 faction of the muscle and tissues involved, accompanied by 

 abundant gas production, which results in prostration, complete 

 collapse, and death in a short time. The degree of infection 

 depends on the virulence of the culture. 



While no experiments were made to determine the presence 

 of a soluble toxin, yet by eliminating certain factors evidence 

 points strongly to the fact that the local infection and lethal 

 effects of this organism are due to a specific bacterial toxin similar 

 to that of the diphtheria bacillus, as already demonstrated by 

 Bull and Pritchett, 1917. The factor of acidity of the culture 

 appears to be secondary in its effect to its toxic action. 



Table 9 gives the results of 55 experiments made on the patho- 

 genicity of cultures of Clostridium Welchii isolated from the fol- 

 lowing sources, human feces 9, cow feces 10 and milk 11. Two 

 cubic centimeters of an eight-hour glucose broth culture were 

 inoculated subcutaneously. 



Spores from cultures obtained from market milk and human 

 feces, after heating to 80°-82° for fifteen minutes to kill the 

 vegetative forms, did not germinate when injected into the 

 circulation or subcutaneous tissues of guinea-pigs or rabbits and 

 the animals showed no reaction. 



